Any time somethings like this happens people rejoice and hope for affordable apartments. I think you are wrong on both accounts.

Converting office buildings into housing is harder than tearing them down and building a apartments from the ground up. Every design of the office is wrong for living: the wall placements, windows, plumbing, hvac, stairs, elevators, etc.

And I also think you are wrong in being happy that these buildings are losing tenants. This will have a significant economic on the investors (which could even be you through funds, pensions, etc), and locally on the area. Think about all the businesses and jobs that serve these offices. These areas are going to decay and that will last for decades until it will be economically viable to repurpose them. At least on the short term I am not happy to see this happening.